JP2009253233A - Inner-layer substrate for common-mode choke coil, its manufacturing method, and common-mode choke coil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inner-layer substrate for a common-mode choke coil capable of stably manufacturing it even with shorter distance in between a pair of coil conductors. <P>SOLUTION: The inner-layer substrate for the common-mode choke coil is equipped with a substrate 11, a first coil conductor 12c and one leading electrode 12a formed on one principal surface, another leading electrode 12b connected to another end of the coil conductor 12c by a through-hole conductor 12d, first insulating layers 14a, 14b covering a first coil 12, a second coil conductor 13c and one leading electrode 13a formed on the first insulating layers, a second insulating layer 15a formed to cover the second coil conductor 13c and one leading electrode 13a, and another leading electrode 13b formed on the second insulating layer 15a. Generation of warpage is prevented when the insulating layer is formed to cover the first coil. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an inner layer substrate for a common mode choke coil, and more particularly to an inner layer substrate for a common mode choke coil that can stably produce a laminated common mode choke coil.

As a conventional common mode choke coil, a stacked common mode choke coil is proposed in which the outer sides of a pair of coil conductors formed so as to face each other in the thickness direction through an insulating layer are sandwiched between a pair of magnetic plates. Has been.
Specifically, in Patent Document 1, as shown in FIG. 15, a pair of coil conductors 112 (112a, 112c), 113 (113a) formed so as to face each other in the thickness direction via an insulator layer 115a. , 113c) is formed as a thin film on one magnetic plate 111, and the other magnetic plate (not shown) is attached to the common mode choke coil 110.
Further, in Patent Document 2, as shown in FIG. 16, for example, a laminated common in which conductor patterns 212 (212a, 212c) and 213 (213a, 213c) are formed on the upper and lower surfaces of a glass / epoxy resin substrate 211, respectively. A mode choke coil 210 is described as prior art.
JP-A-8-203737 JP 2000-277354 A

  However, in the common mode choke coil 110 described in the former background art, since the pair of coil conductors 112 and 113 are formed as a thin film on one magnetic material plate 111, the magnetic material substrate 111 is handled during handling such as a machining process. There was a problem that burrs and cracks were likely to occur. In the common mode choke coil 210 described in the latter background art, it is difficult to reduce the thickness of the glass / epoxy resin substrate 211 in consideration of the handleability of a processing process such as etching. For this reason, the distance between the pair of coil conductors 212 and 213 is increased, and there is a problem that it is difficult for the common mode choke coil 210 to have high characteristics (degree of coupling).

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an inner substrate for a common mode choke coil that can be stably produced even if the distance between a pair of coil conductors is reduced. . Another object of the present invention is to provide a common mode choke coil that can be easily produced using an inner layer substrate for a common mode choke coil. Another object of the present invention is to provide a manufacturing method capable of stably obtaining the inner layer substrate for a common mode choke coil.

The inner layer substrate for the common mode choke coil of the present invention is
(1) a non-magnetic insulating substrate;
A first coil conductor formed on one main surface of the substrate and one extraction electrode connected to one end of the coil conductor;
A first coil together with the first coil conductor and the one extraction electrode is connected to the other end of the first coil conductor by a through-hole conductor formed on the other main surface of the substrate and penetrating the substrate. The other extraction electrode constituting
A first insulator layer formed on each main surface of the substrate so as to cover the first coil;
A second coil conductor formed on the first insulator layer on one main surface side of the substrate so as to face the first coil conductor and the one extraction electrode, and one end of the coil conductor are connected. One extraction electrode,
A second insulator layer formed to cover the second coil conductor and one extraction electrode;
Along with the second coil conductor and the one extraction electrode, the second coil conductor is formed on the second insulator layer and connected to the other end of the second coil conductor by a via-hole conductor penetrating the second insulator layer. The other extraction electrode constituting the second coil;
Is provided. (Hereinafter referred to as first problem solving means.)

One of the main forms of the inner layer substrate for the common mode choke coil is: (2) after the first insulator layer covering the first coil is laminated with prepregs on both main surfaces of the substrate, It was formed at the same time by hot pressing. (Hereinafter referred to as the second problem solving means.)

The common mode choke coil of the present invention is
(3) A magnetic substrate is attached to both main surfaces of the inner layer substrate described in the first problem solving means, respectively,
Terminal electrodes are formed on and near the end surface of the substrate so as to be connected to the lead electrode exposed on the end surface of the inner layer substrate. (Hereinafter referred to as third problem solving means.)

In addition, the method of manufacturing the inner layer substrate for a common mode choke coil according to the present invention includes:
(4) forming a first coil conductor and one lead electrode connected to one end of the coil conductor on one main surface of the non-magnetic and insulating substrate;
Forming the other lead electrode connected to the other end of the first coil conductor by a through-hole conductor penetrating the substrate on the other main surface of the substrate to prepare a first coil; ,
Forming a first insulator layer on both main surfaces of the substrate so as to cover the first coil, respectively;
The second coil conductor and the second coil conductor on the first insulator layer on one main surface side of the substrate so as to face the first coil conductor and one lead electrode connected to one end of the coil conductor, Forming one extraction electrode connected to one end of the coil conductor;
Forming a second insulator layer so as to cover the second coil conductor on one main surface side of the substrate and one lead electrode connected to the coil conductor;
Forming a pilot hole in the second insulator layer so as to expose the other end of the second coil conductor;
Forming the other lead electrode on the second insulator layer to connect to the other end of the second coil conductor exposed from the pilot hole;
Is provided. (Hereinafter referred to as the fourth problem solving means.)

In addition, one of the main forms of the method for manufacturing the inner substrate for the common mode choke coil is (5) in the step of forming the second insulator layer on the one main surface side of the substrate, A second insulator layer is formed on the first insulator layer on the other main surface side of the substrate. (Hereinafter, referred to as fifth problem solving means.)

The operation of the first problem solving means is as follows. That is, the first coil is divided and formed on both main surfaces of the insulating substrate, and the second coil facing the first coil is formed of the insulator layer formed on both main surfaces of the substrate. Formed on one of them. For this reason, while being able to make the thickness of the insulator layer arrange | positioned between a 1st coil and a 2nd coil small, generation | occurrence | production of the curvature at the time of forming the insulator layer which coat | covers the said 1st coil is prevented. Is done.

The operation of the second problem solving means is as follows. That is, the first insulator layer covering the first coil is formed simultaneously by laminating prepregs on both main surfaces of the substrate and then hot pressing. For this reason, the shrinkage stress at the time of curing when forming the insulator layer is balanced on both main surfaces of the substrate, and the occurrence of warpage is suppressed.

  The operation of the third problem solving means is as follows. That is, since the magnetic substrate is adhered to both main surfaces of the inner layer substrate described in the first problem solving means, the occurrence of chipping or cracking of the substrate is prevented.

The operation of the fourth problem solving means is as follows. That is, on one main surface of the non-magnetic and insulating substrate, the first coil conductor and one extraction electrode connected to one end of the coil conductor, and on the other main surface of the substrate, Providing the first coil by separately forming the other extraction electrode connected to the other end of the first coil conductor by a through-hole conductor penetrating the substrate;
Forming a first insulator layer on both main surfaces of the substrate so as to cover the first coil, respectively;
The second coil conductor and the second coil conductor on the first insulator layer on one main surface side of the substrate so as to face the first coil conductor and one lead electrode connected to one end of the coil conductor, Forming one extraction electrode connected to one end of the coil conductor. For this reason, the insulator layer located between the first coil and the second coil can be formed thin, and the other main surface side of the substrate is also insulated at the same time when the insulator layer is formed. Since the body layer is formed, the shrinkage stress at the time of curing is balanced on both main surfaces of the substrate, and the occurrence of warpage is suppressed.

The operation of the fifth problem solving means is as follows. That is, in the step of forming the second insulator layer on one main surface side of the substrate, a second insulator layer is simultaneously formed on the first insulator layer on the other main surface side of the substrate. Therefore, even if the thickness of the second insulator layer is increased, the shrinkage stress at the time of curing is balanced on both main surfaces of the substrate, and the occurrence of warpage is suppressed.

  According to the inner layer substrate for a common mode choke coil of the present invention, the thickness of the insulator layer disposed between the first coil and the second coil can be reduced, and the insulator covering the first coil Since the occurrence of warpage when forming the layer is prevented, a common mode choke coil capable of stable production can be provided.

In addition, according to the common mode choke coil of the present invention, since the magnetic substrate is adhered to both main surfaces of the inner layer substrate, the common mode choke that can be stably produced is free from the occurrence of chipping and cracking of the magnetic substrate. A coil can be provided.

In addition, according to the method for manufacturing an inner layer substrate for a common mode choke coil of the present invention, an insulator layer positioned between the first coil and the second coil can be formed thin, and the insulator layer is Since the insulator layer is also formed on the other main surface side of the substrate at the same time, the shrinkage stress at the time of curing is balanced on both main surfaces of the substrate, so that the occurrence of warpage is suppressed and the common mode choke is suppressed. The coil inner layer substrate can be stably produced.

Further, according to the method for manufacturing an inner layer substrate for a common mode choke coil of the present invention, even if the thickness of the second insulator layer is increased, shrinkage stress during curing is balanced on both main surfaces of the substrate, The occurrence of warpage is suppressed, and the inner substrate for the common mode choke coil can be stably produced.
The above object and other objects, structural features, and operational effects of the present invention will become apparent from the following description and the accompanying drawings.

  First, a first embodiment of an inner layer substrate for a common mode choke coil according to the present invention will be described with reference to FIGS. FIG. 1 is an external perspective view showing the entire structure of the common mode choke coil inner layer substrate 10 of the present embodiment. FIG. 2 is a longitudinal sectional view taken along the line AA of FIG. 1 showing the internal structure of the common mode choke coil inner layer substrate 10 of the present embodiment. FIG. 3 is an exploded perspective view showing the internal structure of the common mode choke coil inner layer substrate 10 of the present embodiment. In the figure, 11 is an insulating substrate, 12 (12a, 12b, 12c, 12d) is a first coil, 13 (13a, 13b, 13c, 13d) is a second coil, and 14 (14a, 14b) is a first coil. Reference numeral 1 denotes an insulator layer, and reference numeral 15a denotes a second insulator layer.

The inner layer substrate 10 for the common mode choke coil of this embodiment is
A non-magnetic insulating substrate 11;
A first coil conductor 12c formed on one main surface of the substrate 11 and one lead electrode 12a connected to one end of the coil conductor 12c;
The first coil conductor 12c and the one extraction electrode are connected to the other end of the first coil conductor 12c by a through-hole conductor 12d formed on the other main surface of the substrate 11 and penetrating through the substrate 11. 12a and the other extraction electrode 12b constituting the first coil 12, and first insulator layers 14a and 14b respectively formed on both main surfaces of the substrate 11 so as to cover the first coil 12. ,
A second coil conductor 13c formed on the first insulator layer 14a on one main surface side of the substrate 11 so as to face the first coil conductor 12c and the one extraction electrode 12a, and the coil conductor One extraction electrode 13a connected to one end of 13c;
A second insulator layer 15a formed to cover the second coil conductor 13c and one lead electrode 13a;
The second coil conductor 13c formed on the second insulator layer 15a is connected to the other end of the second coil conductor 13c by a via-hole conductor 13d penetrating the second insulator layer 15a. The other extraction electrode 13b which comprises the 2nd coil 13 with the one extraction electrode 13a is provided.

Next, a first embodiment of a method for manufacturing an inner layer substrate for a common mode choke coil according to the present invention will be described with reference to FIG. 4 (A) to 4 (G) are longitudinal sectional views for explaining the manufacturing method of the common mode choke coil inner layer substrate according to the present embodiment step by step.
The manufacturing method of the inner layer substrate for the common mode choke coil of the present embodiment is as follows:
First, a nonmagnetic insulating substrate 11 is prepared as shown in FIG. 4 (A), and then a first coil is formed on one main surface of the substrate 11 as shown in FIG. 4 (B). One lead electrode 12a connected to one end of the conductor 12c and the coil conductor 12c, and the first coil conductor by a through-hole conductor 12d penetrating the substrate 11 on the other main surface of the substrate 11 The other extraction electrode 12b connected to the other end of 12c is divided and formed to prepare the first coil 12.
Next, as shown in FIG. 4C, first insulator layers 14a and 14b are formed on both main surfaces of the substrate 11 so as to cover the first coil 12, respectively.
Next, as shown in FIG. 4D, the first coil conductor 12c and one end of the coil conductor 12c are connected to the first insulator layer 14a on one main surface side of the substrate 11. The second coil conductor 13c and one lead electrode 13a connected to one end of the coil conductor 13c are formed so as to face the other lead electrode 12a.
Next, as shown in FIG. 4E, the second coil conductor 13c on one main surface side of the substrate 11 and the one extraction electrode 13a connected to the coil conductor 13c are covered. Two insulator layers 15a are formed.
Next, as shown in FIG. 4F, a lower hole 15d is formed in the second insulator layer 15a so as to expose the other end of the second coil conductor 13c.
Next, as shown in FIG. 4 (G), the other lead is connected to the other end of the second coil conductor 13c exposed from the lower hole 15d on the second insulator layer 15a. The electrode 13b is formed. In this way, the common mode choke coil inner layer substrate 10 of the first embodiment shown in FIG. 2 is obtained.

Next, a first embodiment of the common mode choke coil of the present invention using the inner layer substrate 10 will be described with reference to FIGS. FIG. 5 is an external perspective view showing the overall structure of the common mode choke coil 20 of the present embodiment. FIG. 6 is a longitudinal sectional view of the common mode choke coil 20 according to the present embodiment taken along line BB in FIG. FIG. 7 is an exploded perspective view showing the internal structure of the common mode choke coil 20 of the present embodiment.

In the common mode choke coil 20 of the present embodiment, magnetic substrates 16a and 16b are attached to both main surfaces of the inner layer substrate 10 for the common mode choke coil of the first embodiment, respectively. Terminal electrodes 18a, 18b, 19a, 19b are formed on and near the end face of the substrate 10 so as to be connected to the lead electrodes 12a, 12b, 13a, 13b exposed on the end face 10T.

Next, a preferred embodiment of each part of the common mode choke coil inner layer substrate 10 of the present invention will be described.

First, a preferred embodiment of the nonmagnetic insulating substrate 11 is as follows. That is, as the material of the substrate 11, for example, a glass fiber cloth impregnated with an epoxy uncured resin (FR-4, FR-5), or a glass fiber cloth further combined with a glass nonwoven fabric. It is preferable to select from a B stage substrate called a so-called prepreg such as (CEM-3). The thickness of the substrate 11 is preferably 40 to 60 μm, for example. The substrate 11 preferably has a length of 50 to 120 mm and a width of 50 to 120 mm, for example, in order to collectively create a plurality of common mode choke coils. In addition, in order to form a through-hole conductor that penetrates the substrate 11, it is preferable to form the pilot hole 11 in the substrate 11 in advance by drilling, laser light irradiation, or the like.

Next, preferred embodiments of the coil conductors 12c and 13c and the extraction electrodes 12a, 12b, 13a and 13b are as follows. That is, as the material of the coil conductors 12c and 13c and the extraction electrodes 12a, 12b, 13a and 13b, for example, copper is preferable. The coil conductors 12c and 13c and the extraction electrodes 12a, 12b, 13a and 13b preferably have a thickness of 5 to 20 μm, for example. Moreover, it is preferable that the line width of the said coil conductors 12c and 13c is 10-30 micrometers, for example. The coil conductors 12c, 13c and the extraction electrodes 12a, 12b, 13a, 13b are preferably formed by, for example, copper plating on the seed layer. Moreover, you may form by etching to copper foil.

Next, a preferred embodiment of the through-hole conductor 12d is as follows. That is, copper is preferable as the material of the through-hole conductor 12d. The thickness of the through-hole conductor 12d is preferably 5 to 10 μm, for example. The diameter of the through-hole conductor 12d is preferably 30 to 100 μm, for example. The through-hole conductor 12d is preferably formed by, for example, chemical plating of copper. Moreover, it is preferable to further electroplate copper on the copper plating film.

Next, a preferred embodiment of the via-hole conductor 13d is as follows. That is, the material of the via-hole conductor 13d is preferably copper, for example. The via hole conductor 13d preferably has a thickness of 5 to 10 μm, for example. The diameter of the via-hole conductor 13d is preferably 30 to 100 μm, for example. The via hole conductor 13d is preferably formed by, for example, chemical plating of copper. Moreover, it is preferable to further electroplate copper on the copper plating film.

Next, preferred embodiments of the first insulator layers 14a and 14b and the second insulator layer 15a are as follows. That is, as the material of the first insulator layers 14a and 14b and the second insulator layer 15a, a so-called prepreg B in which a glass fiber cloth is impregnated with an epoxy uncured resin such as FR-4. It is preferable to select from a stage substrate. The thickness of the first insulator layers 14a and 14b and the second insulator layer 15a is preferably 10 to 40 μm, for example. Moreover, it is preferable to form the said 1st insulator layers 14a and 14b and the 2nd insulator layer 15a by laminating | stacking the said prepreg on the main surface of the said board | substrate 11, for example, and hot-pressing.

Next, a preferred embodiment of the magnetic substrates 16a and 16b is as follows. That is, the material of the magnetic substrates 16a and 16b is preferably selected from, for example, a ferrite magnetic powder, a composite magnetic sheet formed by mixing metal magnetic powder and a resin, a sintered ferrite plate, or the like. The thickness of the magnetic substrates 16a and 16b is preferably 200 to 400 μm, for example. In addition, the magnetic substrates 16a and 16b are adhered to both main surfaces of the common mode choke coil inner layer substrate 10 using, for example, an adhesive sheet or adhesive mainly composed of epoxy resin, polyphenylene ether (PPE), or the like. It can be used as an adhering means, for example, by applying a heat treatment such as hot pressing at 180 ° C.

Next, preferred embodiments of the terminal electrodes 18a, 18b, 19a, 19b are as follows. That is, as the material of the terminal electrodes 18a, 18b, 19a, 19b, it is preferable to use a metal selected from silver, copper, nickel or the like, or a conductive resin in which the metal particles are contained in the resin. The terminal electrodes 18a, 18b, 19a, 19b preferably have a thickness of 20 to 80 μm, for example. The terminal electrodes 18a, 18b, 19a, and 19b are formed by, for example, mixing the metal powder and resin to form an electrode material paste, applying the paste, and then heat-treating it at, for example, 150 ° C. to cure. Is preferred. Further, it is preferable to form a film with good solderability such as Sn plating on the obtained electrode film. Further, the present invention is not limited to the application / curing of the electrode material paste. For example, after forming a seed layer by sputtering copper, an electrode film made of the metal may be grown on the seed layer by, for example, electrolytic plating. Good.

Example 1
Next, examples of the inner layer substrate for a common mode choke coil of the present invention will be described.
First, as shown in FIG. 4A, a nonmagnetic insulating substrate 11 made of FR-4 and having a length of 120 mm, a width of 120 mm, and a thickness of 60 μm was prepared. In the substrate 11, a pilot hole 11 d having a diameter of 60 μm was previously formed by laser beam irradiation at a position where a through-hole conductor was to be formed later.
Next, as shown in FIG. 4B, a seed layer (not shown) was formed by chemical plating of copper on both main surfaces of the substrate 11 and the inner peripheral surface of the lower hole 11d. Next, a 20 μm thick film made of a photosensitive resin was adhered on the seed layer to form a resist film. Next, after exposing using a predetermined mask and removing an unnecessary resist film, copper is electroplated, and one of the first coil conductor 12c having a thickness of 10 μm and one end connected to one end of the coil conductor 12c. The lead electrode 12a and the other lead electrode 12b connected to the other end of the first coil conductor 12c by the through-hole conductor 12d penetrating the substrate 11 on the other main surface of the substrate 11, The first coil 12 was prepared by dividing each of them.
Next, as shown in FIG. 4C, prepregs made of FR-4 are laminated on both main surfaces of the substrate 11 so as to cover the first coil 12, respectively, and hot-pressed at 180 ° C. for 80 minutes. Thus, the first insulator layers 14a and 14b having a thickness of 20 μm were formed.
Next, as shown in FIG. 4D, the first coil conductor is plated on the first insulator layer 14a on one main surface side of the substrate 11 in the same manner as described above. 12c and one extraction electrode 13a connected to one end of the coil conductor 13c, and a second coil conductor 13c having a thickness of 10 μm so as to face the one extraction electrode 12a connected to one end of the coil conductor 12c. Formed.
Next, as shown in FIG. 4E, the prepreg is laminated and heat-pressed in the same manner as described above, and connected to the second coil conductor 13c on one main surface side of the substrate 11 and the coil conductor 13c. A second insulator layer 15a having a thickness of 20 μm was formed so as to cover the one extraction electrode 13a.
Next, as shown in FIG. 4 (F), a laser beam is irradiated to prepare a pilot hole having a diameter of 60 μm so that the other end of the second coil conductor 13c is exposed to the second insulator layer 15a. 15d was formed.
Next, as shown in FIG. 4G, copper is plated and connected to the other end of the second coil conductor 13c exposed from the lower hole 15d on the second insulator layer 15a. Thus, the other extraction electrode 13b having a thickness of 10 μm was formed. Thus, the common mode choke coil inner layer substrate 10 of the first embodiment shown in FIG. 2 was obtained.

Next, a second embodiment of the inner layer substrate for a common mode choke coil according to the present invention will be described with reference to FIGS. FIG. 8 is an external perspective view showing the entire structure of the common mode choke coil inner layer substrate 30 of the present embodiment. FIG. 9 is a longitudinal sectional view taken along the line CC of FIG. 8 showing the internal structure of the common mode choke coil inner layer substrate 30 of the present embodiment. FIG. 10 is an exploded perspective view showing the internal structure of the common mode choke coil inner layer substrate 30 of the present embodiment. In the figure, 31 is an insulating substrate, 32 (32a, 32b, 32c, 32d) is a first coil, 33 (33a, 33b, 33c, 33d) is a second coil, and 34a, 34b is a first insulation. The body layers 35a and 35b are second insulator layers.

The inner layer substrate 30 for the common mode choke coil of this embodiment is
A non-magnetic insulating substrate 31;
A first coil conductor 32c formed on one main surface of the substrate 31 and one lead electrode 32a connected to one end of the coil conductor 32c;
The first coil conductor 32c and the one extraction electrode are connected to the other end of the first coil conductor 32c by a through-hole conductor 32d formed on the other main surface of the substrate 31 and penetrating the substrate 31. The other extraction electrode 32b that constitutes the first coil 32 together with the first coil 32; first insulator layers 34a and 34b formed on both main surfaces of the substrate 31 so as to cover the first coil 32; ,
A second coil conductor 33c formed on the first insulator layer 34a on one main surface side of the substrate 31 so as to face the first coil conductor 32c and the one extraction electrode 32a, and the coil conductor One extraction electrode 33a connected to one end of 33c;
Covering the second coil conductor 33c and one lead electrode 33a on one main surface side of the substrate 31 and covering the first insulator layer 34b on the other main surface side of the substrate 31 Second insulator layers 35a and 35b respectively formed,
A via-hole conductor 33d is formed on the second insulator layer 35a on one main surface side of the substrate 31 and is connected to the other end of the second coil conductor 33c through the second insulator layer 35a. The other extraction electrode 33b which comprises the 2nd coil 33 with the said 2nd coil conductor 33c and said one extraction electrode 33a is provided.

Next, a second embodiment of the method for manufacturing an inner layer substrate for a common mode choke coil according to the present invention will be described with reference to FIG. FIG. 11A to FIG. 11G are longitudinal cross-sectional views for explaining the manufacturing method of the common mode choke coil inner layer substrate according to the present embodiment step by step.
The manufacturing method of the inner layer substrate for the common mode choke coil of the present embodiment is as follows:
First, as shown in FIG. 11A, a non-magnetic and insulating substrate 31 is prepared. Next, as shown in FIG. 11B, a first coil is formed on one main surface of the substrate 31. The first coil conductor is connected to the conductor 32c and one lead electrode 32a connected to one end of the coil conductor 32c on the other main surface of the substrate 31 by a through-hole conductor 32d penetrating the substrate 31. The other extraction electrode 32b connected to the other end of 32c is divided and formed to prepare the first coil 32.
Next, as shown in FIG. 11C, first insulator layers 34a and 34b are formed on both main surfaces of the substrate 31 so as to cover the first coil 32, respectively.
Next, as shown in FIG. 11D, the first coil conductor 32c and one end of the coil conductor 32c are connected to the first insulator layer 34a on one main surface side of the substrate 31. A second coil conductor 33c and one extraction electrode 33a connected to one end of the coil conductor 33c are formed so as to face the other extraction electrode 32a.
Next, as shown in FIG. 11E, the second coil conductor 33c on one main surface side of the substrate 31 and the one extraction electrode 33a connected to the coil conductor 33c are covered. Also, second insulator layers 35a and 35b are formed so as to cover the first insulator layer 34b on the other main surface side of the substrate 32, respectively.
Next, as shown in FIG. 11F, a lower hole 35d is formed in the second insulator layer 35a so as to expose the other end of the second coil conductor 33c.
Next, as shown in FIG. 11 (G), the other lead is connected to the other end of the second coil conductor 33c exposed from the lower hole 35d on the second insulator layer 35a. The electrode 33b is formed. Thus, the common mode choke coil inner layer substrate 30 of the second embodiment shown in FIG. 9 is obtained.

The common mode choke coil inner layer substrate 30 of the present embodiment is different from the common mode choke coil inner layer substrate 10 of the first embodiment in that the first insulator layer on the other main surface side of the substrate 31 is different. The second insulator layer 35b is formed on the 34b so as to cover the first insulator layer 34b. According to this, even if it is a case where the thickness of the said 2nd insulator layer 35a is thick, generation | occurrence | production of curvature can be suppressed. Other configurations and operational effects are the same as those of the inner layer substrate 10 for the common mode choke coil of the first embodiment, and thus description thereof is omitted.

Next, a second embodiment of the common mode choke coil of the present invention using the inner layer substrate 30 will be described with reference to FIGS. FIG. 12 is an external perspective view showing the overall structure of the common mode choke coil 40 of the present embodiment. FIG. 13 is a longitudinal sectional view of the common mode choke coil 40 of the present embodiment taken along the line DD of FIG. FIG. 14 is an exploded perspective view showing the internal structure of the common mode choke coil 40 of the present embodiment.

In the common mode choke coil 40 of this embodiment, magnetic substrates 36a and 36b are attached to both main surfaces of the inner layer substrate 30 for the common mode choke coil of the second embodiment, respectively. Terminal electrodes 38a, 38b, 39a, 39b are formed on and near the end surface of the substrate 30 so as to be connected to the extraction electrodes 32a, 32b, 33a, 33b exposed on the end surface 30T.

(Example 2)
Next, examples of the inner layer substrate for a common mode choke coil of the present invention will be described.
First, as shown in FIG. 11A, a nonmagnetic insulating substrate 31 made of FR-4 and having a length of 120 mm, a width of 120 mm, and a thickness of 60 μm was prepared. The substrate 31 was previously formed by irradiating a laser beam with a pilot hole 31d having a diameter of 60 μm at a position where a through-hole conductor was to be formed later.
Next, as shown in FIG. 11B, a seed layer (not shown) was formed by chemical plating of copper on both main surfaces of the substrate 31 and the inner peripheral surface of the lower hole 31d. Next, a 20 μm thick film made of a photosensitive resin was adhered on the seed layer to form a resist film. Next, exposure is performed using a predetermined mask to remove an unnecessary resist film, and then copper is electroplated to provide a first coil conductor 32c having a thickness of 10 μm and one lead connected to one end of the coil conductor 32c. The electrode 32a and the other lead electrode 32b connected to the other end of the first coil conductor 32c by the through-hole conductor 32d penetrating the substrate 31 on the other main surface of the substrate 31, respectively. The first coil 32 was prepared by being divided.
Next, as shown in FIG. 11C, prepregs made of FR-4 are laminated on both main surfaces of the substrate 31 so as to cover the first coil 32, respectively, and hot-pressed at 180 ° C. for 80 minutes. Thus, the first insulator layers 34a and 34b having a thickness of 20 μm were formed.
Next, as shown in FIG. 11D, the first coil conductor is plated on the first insulator layer 34a on the one main surface side of the substrate 31 in the same manner as described above. The second coil conductor 33c having a thickness of 10 μm and the one extraction electrode 33a connected to one end of the coil conductor 33c are arranged so as to face the one extraction electrode 32a connected to one end of the coil conductor 32c. Formed.
Next, as shown in FIG. 11 (E), the prepreg is laminated in the same manner as described above, and the second coil conductor 33c on one main surface side of the substrate 31 and the one connected to the coil conductor 33c. The second insulator layers 35a and 35b each having a thickness of 20 μm so as to cover the lead electrode 33a and the first insulator layer 34b on the other main surface side of the substrate 31. Formed.
Next, as shown in FIG. 11F, a pilot hole having a diameter of 60 μm is irradiated so as to expose the other end portion of the second coil conductor 33c to the second insulator layer 35a by irradiating with laser light. 35d was formed.
Next, as shown in FIG. 11G, copper is plated and connected to the other end of the second coil conductor 33c exposed from the lower hole 35d on the second insulator layer 35a. Thus, the other extraction electrode 33b having a thickness of 10 μm was formed. Thus, the common mode choke coil inner layer substrate 30 of the second embodiment shown in FIG. 9 was obtained.

1 is an external perspective view showing the overall structure of a first embodiment of an inner layer substrate for a common mode choke coil of the present invention. The longitudinal cross-sectional view which shows the internal structure of the said embodiment. The disassembled perspective view which shows the internal structure of the said embodiment. The longitudinal cross-sectional view which shows 1st Embodiment of the manufacturing method of the inner layer board | substrate for common mode choke coils of this invention. 1 is an external perspective view showing the overall structure of a first embodiment of a common mode choke coil of the present invention. The longitudinal cross-sectional view which shows the internal structure of the said embodiment. The disassembled perspective view which shows the internal structure of the said embodiment. The external appearance perspective view which shows the whole structure of 2nd Embodiment of the inner layer board | substrate for common mode choke coils of this invention. The longitudinal cross-sectional view which shows the internal structure of the said embodiment. The disassembled perspective view which shows the internal structure of the said embodiment. The longitudinal cross-sectional view which shows 2nd Embodiment of the manufacturing method of the inner layer board | substrate for common mode choke coils of this invention. The external appearance perspective view which shows the whole structure of 2nd Embodiment of the common mode choke coil of this invention. The longitudinal cross-sectional view which shows the internal structure of the said embodiment. The disassembled perspective view which shows the internal structure of the said embodiment. Sectional drawing which shows an example of the conventional inner layer board | substrate for common mode choke coils. Sectional drawing which shows the other example of the conventional inner layer board | substrate for common mode choke coils.

Explanation of symbols

10: Inner layer substrate for common mode choke coil.
10T: end face of inner layer substrate 11: substrate 11d: lower hole 12: first coil 12a: extraction electrode 12b: extraction electrode 12c: coil conductor 12d: through-hole conductor 13: second coil 13a: extraction electrode 13b: extraction electrode 13c: coil conductor 13d: via-hole conductors 14, 14a, 14b: first insulator layer 14c: insulator 15, 15a: second insulator layer 15d: pilot holes 16a, 16b: magnetic substrates 17a, 17b: adhesion Agent layers 18a, 18b, 19a, 19b: terminal electrode 20: common mode choke coil 30: inner layer substrate 30T for common mode choke coil: end surface of inner layer substrate 31: substrate 31d: lower hole 32: first coil 32a: extraction electrode 32b: Lead electrode 32c: Coil conductor 32d: Through-hole conductor 33: Second coil 33a: Lead electrode 33b: Lead electricity 33c: coil conductor 33d: via-hole conductors 34, 34a, 34b: first insulator layers 35, 35a, 35b: second insulator layer 35d: lower holes 36a, 36b: magnetic substrate 37a, 37b: adhesive layer 38a, 38b, 39a, 39b: terminal electrode 40: common mode choke coil

Claims (5)

A non-magnetic, insulating substrate;
A first coil conductor formed on one main surface of the substrate and one extraction electrode connected to one end of the coil conductor;
A first coil together with the first coil conductor and the one extraction electrode is connected to the other end of the first coil conductor by a through-hole conductor formed on the other main surface of the substrate and penetrating the substrate. The other extraction electrode constituting
A first insulator layer formed on each main surface of the substrate so as to cover the first coil;
A second coil conductor formed on the first insulator layer on one main surface side of the substrate so as to face the first coil conductor and the one extraction electrode, and one end of the coil conductor are connected. One extraction electrode,
A second insulator layer formed to cover the second coil conductor and one extraction electrode;
Along with the second coil conductor and the one extraction electrode, the second coil conductor is formed on the second insulator layer and connected to the other end of the second coil conductor by a via-hole conductor penetrating the second insulator layer. The other extraction electrode constituting the second coil;
An inner layer substrate for a common mode choke coil, comprising: The first insulator layer covering the first coil is formed simultaneously by laminating prepregs on both main surfaces of the substrate and then hot pressing. An inner layer substrate for a common mode choke coil as described. A magnetic substrate is adhered to both main surfaces of the inner layer substrate according to claim 1, respectively.
A common mode choke coil, wherein a terminal electrode is formed on and near the end surface of the substrate so as to be connected to the extraction electrode exposed on the end surface of the inner layer substrate. Forming a first coil conductor and one lead electrode connected to one end of the coil conductor on one main surface of the non-magnetic and insulating substrate;
Forming the other lead electrode connected to the other end of the first coil conductor by a through-hole conductor penetrating the substrate on the other main surface of the substrate to prepare a first coil; ,
Forming a first insulator layer on both main surfaces of the substrate so as to cover the first coil, respectively;
The second coil conductor and the second coil conductor on the first insulator layer on one main surface side of the substrate so as to face the first coil conductor and one lead electrode connected to one end of the coil conductor, Forming one extraction electrode connected to one end of the coil conductor;
Forming a second insulator layer so as to cover the second coil conductor on one main surface side of the substrate and one lead electrode connected to the coil conductor;
Forming a pilot hole in the second insulator layer so as to expose the other end of the second coil conductor;
Forming the other lead electrode on the second insulator layer to connect to the other end of the second coil conductor exposed from the pilot hole;
A method for manufacturing an inner layer substrate for a common mode choke coil, comprising: In the step of forming the second insulator layer on one main surface side of the substrate, simultaneously, forming a second insulator layer on the first insulator layer on the other main surface side of the substrate 5. The method for manufacturing an inner layer substrate for a common mode choke coil according to claim 4, wherein:

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